While the cleaning of dishes, glasses and cutlery and the removal of food residues by means of the conventional mechanical dishwashers and the detergents offered by the trade generally does not present any special problems, considerable difficulties are sometimes encountered with dried-on or special food residues, such as dried starch residues. Beyond that, it is frequently not possible in commercial enterprises, like restaurants, company canteens, hospitals, large bakeries or food factories to clean pots, pans, baking molds, etc., with baked-on food residues mechanically in the same manner. The water temperatures and water turbulences in these machines in connection with the chemical action of the conventional detergents are not sufficient to detach such firmly adhering residues from their base.
Presently known methods use, therefore, either suspended sand alone or inert granular material together with a dissolved conventional detergent. As an inert granular material have been suggested, for example, coarse particles of calcium carbonate, magnesium carbonate, but also small metal balls. But these methods require necessarily cleaning of the waste water, that is, removal of the coarse particles, or recovery of the metal balls, used as cleaning agents adjunctives.